I have a noise that may just be "
Porsche
" but I'd like to track it down and see if I can make it go away.
Car runs fantastic. Burns no oil, no odd habits, no weird surges or knocks. 1098XX miles.
This noise is a slight metallic flicker/ rattle/ flutter noise that only occurs sometimes when the engine is warmed up and steady state. I don't notice it while the rpms are rising or falling. IT isn't constant and sometimes goes away. Happens rolling and static, clutch in and clutch out.
Video is attached and it is barely audible in the background of normal engine noise.
Definitely hear it reflected from hard surfaces and less so from inside the car.
I've hammered on the manifolds and cats and not noticed any major rattles. Tapped around on heat shields and such under the car.
My guesses are:
1> Cam chains/ guides/ tensioners. But I would expect to be able to hear it big time at idle and it clearly starts at 2000 RPM.
My gut feeling is that this is guides or a tensioner problem.
2> Cats. Nothing rattled big time when I hammered on them...but the car had cooled about 20 mins so maybe they stop rattling once cooled off?
3> Heat shields. I've tapped and pushed and pulled and found nothing overtly loose.
4> Belts/ pulleys/ water pump. I've pulled the belt and spun all the pulleys. THe water pump has a little forward and back play and a faint bearing tick kind of feel. I have a new water pump in the garage waiting on time to install....but don't feel that is the issue.
Research for similar complaints I find some note that its just the sound the vario cam makes.
Just changed the oil to lubromoly 5w-40 and no change. No flakes or anything in filter at 5500 miles. Nothing untoward in last oil analysis at 103XXX.
Any ideas?
Thanks for any posts.
Here is the video.....
Porsche 2.9 987.2 noises....
One more wild card for you....check the brackets / clamps around the
exhaust
/ tips. I know I have to tighten one of them (or swap out one of them)
Good call. I am missing in clamp on one side of the tips. I should replace that.
Am I correct in your video - the noise starts at about 18 seconds? And lasts until
and ends about at 45 seconds?
It sounds like something turning. Since there is Variocam+ action going on in that RPM range, it wouldn't surprise me to hear a difference in engine noise, especially when the + part - variable valve lift is in action.
If you have a good radio, turn it up. It's a Cayman so I can't say "Put your top down..." It doesn't sound like anything of consequence to me - but I also know from my own OCD/paranoid issues how much an undefined noise can sound like a disaster waiting to happen.
Maybe take it to a "pro" and let them dismiss the noise as "nothing to be worried about" might help?
Hey Don, It's pretty much sprinkled in the entire video. definitely between 2k and 3 k. Driving it today and nothing....Changed the oil the other day but I don't think that" fixed" it.
I have some musical instrument recording gear I'll hook up and get a sample.
Anyone ever replace the cam chain tensioners on the 2.9?
I have done that on several
BMW
engines I had that had a little cam chain rattle.
Here is a better recording. I am leaning rattling cats or heat shield.
Did you do the water pump? It sounds like metal to metal tapping, not so much like a loose heat shield. It seems constant over the entire RPM range in your video, reinforcing something mechanical is making the noise vs something loose..
I've got a water pump in the garage waiting to go in. Belt was done recently....I didn't want to run it up to temp with no water pump to see about the noise. I should get it hot and pull the belt.
If this doesn't happen consistently and varies by the temp of air and car, then most likely external parts like heat shield, clamps etc? Our subie does the same depends on the temp...was rusted, disintegrated bolts and head shield. Don would know waaayy better about the internals though
So when I was replacing my suspension I decided to remove and replace the manifold to
exhaust
connections. Especially since access is GREAT when there is no suspension in the way.
Good news is that the noise I had is GONE.
Two possible reasons....
Maybe the noise was a loose connection since the nuts/ studs were clearly rusted and compromised.
Maybe the air chisel vibrated something loose (or tight) that was vibrating in the
exhaust
.
I can't think of anything else I touched that would have made the noises I had heard.
Serentipidous fix - a fix that happens when you're fixing something else. PERFECT! I love it!
Car still made some cam chain noise so I replaced the lower (easier to get to) cam chain tensioner and 95% of any cam chain noise went away. The top tensioner is a bitch to get to so I will do that one when I have a reason to do other work up there. (simply unbolt and slide out of the way the AC compressor to access the tensioner....which you really need to pull accesory belt and remove the intake manifold to do....oh hell no....not today)
The bottom tensioner is literally a 2 minute job once the car is in the air. I didn't lock the motor, I just pulled the tensioner and swapped and retorqued. Maybe playing with fire by doing that so YMMV but I just couldn't see the cam chain jumping timing by simply having the tensioner released. No motor I've ever been in ever got enough slack you could move the timing, if you even wanted to, by simply releasing the tensioner.
I prefilled the tensioner with oil by submerging in fresh oil, then pushing in the plunger a few times to burp it. I did not even crank the car with no fuel pressure to fill it. I simply started and was going to turn off it it really rattled....but it sounded perfect from the first moment so I let it idle a few minutes.
The new tensioner was noticably stiffer with the spring rate. Can't comment on if the pressure changed with the hydraulically operated tensioner but it must have with the reduciton in noise.
By the way...do not order orings or washers when you order a tensioner....thay come installed on the new part.
